Ball mill



Nov. 23 1926. 7 1,607,858

attozncq Nov. 23 1926.

J. A..AYCKER BALL MILL 3 Sheets-Sheet 5 Filed June 6 Patented Nov. 23, 1926.

UNITED STATES,

1,607,858 PATENT OFFICE.

JOHN A ACKER, 01 PORT HURON, MICHIGAN, ASSIGNOR TO TRAYLOR ENGINEERING & MANUFACTURING COMPANY, OF ALLENTOWN, P

TION OF DELAWARE.

The present invention aims to provide a mill having radially arranged grate bars which are of identical size and configuration, whereby they are interchangeable and 6 are readily assembled.

The invention further aims to provide a With these and other objects which will hereinafter appear, the invention includes the novel features of construction and arrangement and combination of parts hereinafter described and particularly defined by the appended claims.

An embodiment of my invention is illustrated in the accompanying drawings, in which:

Figure 1 is a longitudinal vertical section through such a mill.-'

Fig. 2 is an enlarged sectional View on a similar section line, but showing but one of the screens and a portion only ofthe drum.

Fig. 3 is a face view of one of the screens with a drum in section and, parts brokgn away or omitted.

Fig. 4 is a detail plan View of one of the grate bars.

Figs. 5 and 6 are sections on lines 55 and 6-6 respectively, of Fig. 4, and, b Figs. 7 and 8 are views'of a wedge mem- Referrin by reference characters to these drawings, t e numeral 1 designates the steel shell of the drum and 2 the lining, which elements may be of the ordinary or any desired construction, as also may the feed and discharge trunnions and driving means, all of which are too well known to those skilled in the art to require description herein. Located adjacent the discharge end of the drum is a screen 3, and between the feed and discharge ends are located other screens 3 and 3 of similar construction, the only difference being that the screen 3 is secured directly to the end of the drum, while the screens 3 and 3 are held in position by means ofspider plates, as will hereinafter more fully appear. While I have, in the present drawings, shown two intermediate screens, it will be understod that th1s is by ENNSYLVANIA, A CORPORA- BALL MILI].

Application filed June 6 1925. Scrial No. 35,865.

way of example only, as one or more may be used as desired. I

Referring first to Figs. 2 and 3, which show one of the intermediate screens, the numeral 4 designates a screen supporting member in the shape of a circular diaphragm havingan angularly turned periphsecured to the steel shell between adjacent lining sections. This diaphragm has an open centers serving as a passage for the fine material separated by the screen, and radial lifter blades 4, which lifter blades support at their inner ends a circular deflector plate 4 which is preferably formed integral therewith. Said lifter blades also 'carry an annular ring 4 (preferably integral therewith), having its face 4 flush with the faces or edges 4 of the ribs, which faces are flared or inclined outwardly from the deflector plate at an acute angle to a plane perpendicular to the axis of the drum.

The diaphragm as thus described, with its lifter blades, deflector plate and annular ring, may be formed as a one piece casting, and is designed to support the grate bars, as hereinafter described. The grate bars are shown at 5 and are all of identical shape so .that they are interchangeable, and by making them all identical in shape, the cost of manufacture is reduced by reason of less equipment being required, and it also further facilitates assembly.

Each grate bar comprises a tapered member having relatively wider inner and outer ends 5 and 5", and preferably also widenederal flange 4 bolted or otherwise suitably reduced portions 5 forming between them elongated openings for the passage of the fine material. Preferably also the grate bars have their walls 5 'tapered downwardly so that the spaces between the grate bars are downwardly flared whereby tendency of the screen to clog is avoided.

In the screen construction shown in the drawingsI use two annular rows of grate bars, the innerends of the inner rows resting against and being supported by the peripheral'edge of the deflector plate 4, which has an inc'lmed face portion forming a seat for the ends of the bars. The inward thrust of the grate bars is sustained by a central.

plate member 6 secured to the deflector plate 4* by means such as a bolt 6 The outer ends of the inner series of grate bars are supported by the'annular ring 4, as also are the inner ends of the outer series of grate bars. The outer ends of the outer seris rest in annular seats formed in thering member 7 bolted or otherwise secured to the shell of the; drum, the outer edges or corners 'of the lifter blades being rebated to form space for this ring. The outer ends of the outer series of grate bars" and the inner ends of the inner series, and also the seat portions of the. ring 7 and plate 6, are so shaped that when the grate bars are in I position they will be interlocked therewith ends towards the axis of the drum, the sides of the grate bars being then radially disposed. To cause them to accurately fit in position to form the outer series, it .is only necessary to reverse an occasional grate bar, as clearly shown in Fig. 3.

After the grate bars have they are crowded laterally into close contact to hold them rigidly against movement, by interposed radially disposed, wedge members 10, secured in position by bolts 11. Preferably the abutting ends of the segment shaped wedges 8 are .rebated to receive the ends of the radially disposed wedge members 10. The diaphragm member 4 on the side opposite the screen, is preferably faced with wear plates 12 which may be held in position by the clamping action of the bolts 9 and 11, and for purposes of lightness, thediaphragm member 4 could be provided with openings, such as indicated at 4", which openings would be closed by the wear plates.

The screen at the discharge end of the drum is identical with the intermediate screen above described, with the exception that the end wall 1 of the drum takes the place of the diaphragm.

From the foregoing description it will be apparent that I rovide a ball mill having a screen which wi l have a maximum amount of port area, and one in which the parts are readily assembled, or replaced in caseof breakage, and in which the parts will be firmly held when in use.

'By the use of a conical screen surface, I secure a maximum of self-clearing effect as the fall of the balls clears the screen apertures. If a broken ball is jammed into one radially towards the shell been assembled of the spaces the constant pounding of the grinding balls on the angular surface of the grate causes the particle to work down or and very often releases it. e

The..angular position also facilitates the discharge of the fine material, because it falls through radially and does not move laterally any distance, which would be required with a flat screen surface.

which could be secured by making the grate bar supporting edges of the lifter bars parallel to-the screen supporting diaphragm 4, the construction remaining otherwise the same.

Having thus described my invention, what I claim is 1. In a ball mill, a cylindrical drum having a grate comprising a plurality of concentrically arranged series of grate bars, each series comprising a plurality of individual grate bars, the grate bars of all of said series being radially disposed and being of uniform size and shape.

2. In a ball mill, a cylindrical drum having a plurality. of annularly arranged series of tapered grate bars, the grate bars of each series being radially disposed relative to the axis of the drum, and all of said grate bars being uniformly tapered, certain of the grate bars of the outer series being reversed in position relative to the remainder of the bars of the series.

3. In a ball mill. the combination with a cylindrical drum of a transverse wall member having an axial discharge port and a plurality of substantially radial lifter blades having inclined .edges, a central deflector plate carried by the inner ends of said lifter blades, and screen members carried by the inclined edges of said lifter blades. 4

4. In a ball mill, the combination with a cylindrical drum, of a transverse wall member having an axial discharge passage,sub-

stantially radial lifter blades having inclined v edges, a central deflector plate carried by sa d blades, an annular ring carried by said blades intermediate the central plate and drum wall, an outer supporting ring adjacent the drum wall, said inner plate and outer ring having concentric thrust sustaining abutments, inner and outer series of rad ally disposed grate bars having ends supported respectively by said plate and outer ring, and juxtaposed ends supported by said intermediate ring, and wedges located between said juxtaposed ends with means for holding them in place.

6. In a ball mill, the combination with a cylindrical drum, of a transverse wall member having an axial discharge passage, substantially radial lifter *blades having inclined edges, a central deflector plate carried by said blades, an annular ring carried by said blades intermediate the central plate and drum wall, an outer supporting ring adjacent the drum wall, said inner plate and outer ring having concentric thrust sustain: ing abutments, inner and outer series of radially disposed grate bars having ends supported respectively by said plate and outer ring, juxtaposed ends supported by said intermediate ring, and segmentalshaped wedges located between said juxtaposed ends with means for holding them in place. 1

7 In a ball mill, the combination with a cylindrical drum, of a transverse wall mem her having an axial discharge passage, substantially radial lifter blades having inclined edges, a central deflector plate carried by sa d blades, an annular ring carried by said blades intermediate the central plate and drum wall, an outer supporting ring adjacent the drum wall, said inner plate and outer ring having concentric thrust sustain ing abutments inner and outer series of radially disposed grate bars having ends supported respectively by said plate and outer ring, juxtaposed ends supported by said intermediate ring, segmental-shaped wedges located'between said juxtaposed ends, and radially arranged wedges arranged at intervals between the grate bars of each series, with means for holding all said wedges in place. 7

8, In a ball mill, the combination with a cylindrigal drum, of a transverse wall mem ber having an axial discharge passage, substantially radial litter blades having inclined edges, a central deflector plate carried by said blades, an annular ring carried by said blades intermediate the central plate and outer ring having concentric thrust sustainingabutments, inner andvouter series of radial disposed grate liars having ends supported respectively by said plate and outer ring, and juxtaposed ends supported by said intermediate ring, segmental-shaped wedges located between said juxtaposed ends, and radially arranged wedges arranged at intervals between the grate bars of each series,

'a central deflector plate with means for holding all said wedges in place, said radial wedges being in line with the juxtaposed ends of said segmental wedges.

9. In a ball mill, the combination with a cylindrical drum, of a transverse wall member having an axial discharge passage, substantially radial lifter blades having inclined edges, a central deflector plate carried by said blades, an annular ring carried by said blades intermediate the central plate and outer ring having concentric thrust sustaining abutments, inner and outer series of radially disposed grate bars having ends supported respectively by said plate and outer ring, and juxtaposed ends supported by said intermediate ring, segmental-shaped wedges located between said juxtaposed ends, radially arranged Wedges arranged at intervals between the grate bars of said series, with means for holding all said Wedges in place, said radial wedges being in line with the juxtaposed ends of said'segmental wedges, and said segment-shaped wedges having rebates in their sides adjacent their ends to receive the ends of the radial wedges.

10.111 a ball mill the combination with a cylindrical drum, of a transverse wall member having an axial discharge passage, substantially radial lifter blades carried thereby, a-' central deflector plate supported by said blades, an annular abutment carried by said plate, an outer annular supporting ring adjacent the drum wall having an abutment,

an intermediate supporting ring, two series of radially disposed grate bars having ends supported by said plate and outer ring and abutting the abutments thereof, and juxtaposed ends supported by said intermediate ring, and segmental wedges located between said juxtaposed ends. 7

11. In a ball mill the combination with a cylindrical drum, of a transverse wall member having'an axial discharge passage, substantially radial lifter blades carried thereby, acentral deflector plate supported by said blades,an annular abutment carried by said plate, an outer annular supporting ring, two series of radially disposed grate bars having ends supported by said plate and outer ring and abutting the abutments thereof, and.juxtaposed ends supported by sai: plate and outer ring, segmental wedges located between said juxtaposed ends, and radial wedges located at suitable intervals between the radially dsposed bars of each series. 1

12. In a ball mill the combination with a cylindrical drum, of a transverse-wall member having'an axial discharge passage, substantially radial lifter blades carried thereby, supported by said blades, an annular abutment carried by said plate, an outer annular supporting ring, two

series of radially disposed grate bars having ends supported by said plate and outer ring and abutting the abutments thereof, and juxtaposed ends supported by said plate and outer ring, segmental wedges located between said juxtaposed ends, and radial wedges located between the radially disposed grate bars of each series in line with the juxtaposed ends of the segmental wedges.

18. In a ball mill the combination with ahaving ends supportedloy said plate and.

outer ring and abutting the abutments thereof, and juxtaposed ends supported by said plate and outer ring, segmental wedges located between said juxtaposed ends, and radial wedges located between the radially disposed grate bars of each series in line with the juxtaposed ends of the segmental wedges, said segmental wedges having rebated ends to receive the ends of said radial wedges.

' 14. In a ball mill, a screen comprisingconcentric supporting members, radially arranged tapered grate bars carried thereby, and radially arranged tapered wedges arranged between certain of said grate bars with means for holding said wedges in place.

15. In a ball mill, a screen comprising inner, intermediate and outer concentric supporting members, two series of tapered grate bars supported thereby, and radially arranged tapered wedges between certain of the grate bars of each series. I

16. In a ball mill, a screen comprising inner, intermediate and outer concentric supporting members, the inner and outer mem bers havinw thrust abutments, inner and outer radially arranged tapered grate bars having ends abutting said abutments and juxtaposed ends resting on said intermediate member, and segmental wedges interposed between said juxtaposed ends.

17. In a ball mill, a screen comprising inner, intermediate and outer concentric supporting members, the inner and outer members having thrust abutments, inner and outer radially arranged tapered grate bars having ends abutting said abutments and juxtaposed ends resting on said intermediate member, and segmental wedges interposed between said juxtaposed ends, and radially disposed tapered wedges interposed between certain of said grate bars.

18. In a ball mill, a screen comprising inner, intermediate and outer concentric supporting members, the inner and outer membershaving thrust abutments, inner and outer radially arranged tapered grate bars having ends abutting said abutments and juxtaposed ends resting on said intermediate member, segmental wedges interposed between said juxtaposed ends, and radially disposed tapered wedges interposed between certain of said grate bars, said radial Wedges being located in line with the juxtaposed ends of the segmental wedges and being longer than the grate bars, the ends of the segmental wedges being rebated to receive the ends of the radial-wedges.

19. In a ball mill, a screen comprising inner, intermediate and outer concentric supporting members, two concentrioannular series of screen members supported thereby, and annular wedging means interposed between the juxtaposed edges of said inner and. outer series of screen members.

20. In a ball mill, a cylindrical drum, acentral plate rigidly supported within the same in a plane transverse to the axis thereof, an annular ring rigidly supported within the drum adjacent the annular wall-thereof, an annular ring rigidly supported within the drum intermediate the central plate and annular ring, said central plate and outer annular ring having concentric thrust sustaining abutments, an inner and outer annular series of screen members having ends supported respectively by said inner plate and outer ring, and juxtaposed ends supported by said intermediate ring, and annular wedging1 means located between said juxtaposed en s.

- 21. In a ball mill, the combination with a cylindrical drum, of a transverse wall member having an axial discharge passage, substantially radial lifter blades having inclined edges, a central deflector plate carried by said blades, an annular ring carried by said blades intermediate the central plate and drum wall, an outer supporting ring adjacent the drum wall, said central plate and outer ring having "thrust sustaining abut ments, inner and outer seriesof screen members having ends supported respectively by said central plate and outer ring and abutting the thrust sustaining abutments thereof, and having juxtaposed ends supported by said intermediate ring, and annular wedging means located between said' juxtaposed ends.

In testimony whereof. I afiix my signature.

7 JOHN A. ACKER. 

